As washing machines (e.g., dish washers, create washers, bottle washers, instrument washers, clothes washers, etc.) have become more sophisticated, systems have been implemented to automatically feed such machines with products (e.g., detergents, sanitizers, rinse aids, chemicals, and the like) which may be produced in liquid, condensed, compressed, granulated, and/or powdered form. Such materials may be automatically delivered to a variety of types of washing machines, and their concentration monitored using a variety of methods.